As is well known, vehicles and machines require some means for measuring the amount of fluid in their system tanks. In virtually all off-highway machine and vehicle applications, the simplest, and probably the most well-known, measuring means is the common dipstick or fluid level measuring gauge. Generally, an elongated fluid level access chamber or tube is provided which is in communication with the interior of the fluid reservoir. The access chamber is of course, adapted to receive and retain the fluid level measuring gauge until such time as it is removed for measuring purposes.
The typical gauge includes an elongated, usually flat, flexible member which extends through the chamber and into the reservoir. The end of the gauge is provided with suitable fluid level measuring indicia so that when the gauge is removed from the access chamber, the amount by which the fluid falls short of being full can be determined.
In the past, the access chamber has been straight or, at most, has included a relatively slight, simple bend. However, current designs in the past few years, particularly in off-highway machines, have become increasingly more curved and convoluted, due to the limited hardware real estate under the hood or within the housing area. Due to the size of the transmission or engine compartment, the size of the transmission or engine itself, and the large number of accessories that have been added to those assemblies, engineers have found it increasingly difficult to locate the access chamber. As a result, the chamber of current off-highway machines, petroleum transmissions, and vehicles oftentimes have a number of bends, one or more of which may be compound bends. As referred to herein, a compound bend is one in which an angular change occurs in more than one plane. Additionally, such access chambers may include two or more consecutive bends which lie in different planes. Such irregularly-shaped access chambers make it exceedingly difficult to insert, remove, and accurately read a flat, straight gauge. Yet further, the access chamber may have a changing inner diameter (ID) or one or more chamfered shoulder zones, further increasing the difficulty of inserting and accurately utilizing the fluid level gauge.
With regard to fluid level gauges with a flat blade, the problem arises as a result of the resistance of the gauge to bending motion in the plane parallel to its flat surface. When a bend in the access chamber requires that the gauge bend in this plane, the leading end of the gauge tends to engage and drag along the wall of the access chamber thus hindering passage of the gauge through the chamber and preventing an accurate read. In other words, the end of the gauge jams against the sides of the chamber in the vicinity of bends, thus inhibiting or preventing free movement of the gauge through the chamber. This problem is also encountered in gauges having round cross sections since once the gauge has been curved in one plane, it resists bending in other planes.
It has been contemplated to provide a gauge with a curved or twisted blade as seen in U.S. Pat. No. 7,191,542 issued to Oyama et al. While the gauge has a twisted shape provided on purpose to continue to a front edge of the measuring section, and where the twisted portion continuously twists from a tip of the gauge to a curved portion, it fails to have a continuously twisted blade section below and above a substantially flat measuring section therebetween. The Oyama patent does not suggest, teach or disclose the multiple twisted sections, each at approximately 180 degree angles, providing flexibility for enhanced gauge travel through the convoluted access chambers, especially at the end where the focus is primarily only on the measuring section.
Further, U.S. Pat. No. 4,021,924 issued to Haines attempts to overcome another problem described above by providing a friction reducing means comprising a roller member mounted so that it rotates in a plane, which is substantially parallel to the plane of the measuring member. The Haines patent suffers from at least one deficiency in that the friction reducing member is made of numerous separate parts riveted together which add to assembly time and manufacturing costs. Additionally, Haines teaches the use of separable parts that may easily wear (roller bearings, rivets, etc.), increasing the likely hood of failure after frictional encounters during assertion and removal of the gauge. Yet further, Haines does not teach, suggest, or contemplate having a twisted zone, with at least one complete 360 degree twist, located immediately adjacent to a spherical chamfer advancing guide.
Further, the prior art does not contemplate nor address the problems associated with easily, accurately, and inexpensively reading the fluid levels when the fluid is cleaner and thus a more clear and transparent color.
Up to this point, little or no sucessful developments have been claimed to alleviate the above-described combination of problems associated with fluid measuring devices, especially with regard to the high powered transmissions of the petroleum and agricultural off-highway machines or engines. Accordingly, the instant disclosure provides a novel combination of a lower cost, highly effective fluid level measuring gauge for accurately measuring fluid levels in a fluid level chamber having one or bends and interior chamfered shoulder zones.